1. Field of the Invention
The invention relates to a multilayered board comprising a material board and, in particular, a multilayered board having a visible surface coated with at least one paper layer impregnated with resin.
2. Discussion of Background Information
It is known to coat wood-based materials such as chipboards, fiberboards, e.g., MDF boards (Medium-Density Fiberboard) or HDF boards (High-Density Fiberboard) or OSB boards (Oriented Structural Board) with decorative papers that are preferably impregnated with aminoplastic resins. Furthermore, it is known to coat continuous pressure laminates (CPL), which: are formed by stacking several paper layers, with decorative papers that are preferably impregnated with aminoplastic resins. As a rule, the decorative papers used for this have a weight per unit area of 45 to 140 g/m2. Usually the resins used for impregnating the paper webs are polycondensation products of melamine with formaldehyde. However, polycondensation products are also used which have a mixed polycondensation of urea and/or melamine with formaldehyde.
In the production of the paper impregnated with resin, the base papers are impregnated with the above-mentioned resins in special impregnation installations. Subsequently decorative papers impregnated in this manner and cut to size are laid on one side or on both sides of material boards and pressed in multi-stage presses, short-cycle presses, or continuous presses (feed-through presses) to form a decorative product, which is then marketed, e.g., as a decorative board, countertop, or flooring element.
To obtain a desired surface structure of the decorative products or the decorative papers, chromium-plated pressing plates are mostly used in the presses, wherein the pressing plates are embodied with corresponding surface structures. A “structure” thereby means not only relief structures, such as a wood structure or a stone structure, but also gloss structures, such as high gloss, pearl gloss, or matt gloss.
An optically high-gloss surface is thereby defined according to the standards DIN 67530, ISO 2813, ASTM D 523 and BS 3900 Part D5 such that the surface has a value of more than 60 gloss units at an angle of incidence of 20° with respect to the surface plane. Surfaces that have a value of 10 to 70 gloss units at an angle of incidence of 60° with respect to the surface plane are called medium-gloss surfaces, while matt-gloss surfaces have fewer than 10 gloss units at an angle of incidence of 60°.
While optically matt-gloss surfaces can be obtained with all of the above-mentioned press types, the production of optically high-gloss surfaces has hitherto been possible only in multi-stage presses with subsequent re-cooling.
However, due to the necessary re-cooling phase, the use of multi-stage presses to produce multilayered boards with high-gloss surfaces has the disadvantages of a high energy consumption and a long production period, since the entire press cycle lasts 15 to 25 minutes. On the other hand, with a short-cycle pressing process, the press cycle lasts only 10 to 30 s, and in the continuous manufacturing process a press cycle actually lasts only 5 to 10 s.